分散液液微萃取-高效液相色谱法测定杂粮中3种甲氧基丙烯酸酯类杀菌剂的残留量

Determination of Residues of 3 Methoxyacrylate Fungicides in Coarse Grains by High Performance Liquid Chromatography with Dispersive Liquid-Liquid Microextraction

基于天然生物衍生溶剂的分散液液微萃取(DLLME),结合高效液相色谱法测定杂粮中嘧菌酯、吡唑醚菌酯、肟菌酯等3种甲氧基丙烯酸酯类杀菌剂的残留量。取过筛后的样品1.0 g于10 mL离心管中,加入800μL乙腈(分散剂),涡旋,取上清液500μL,加入200μL 4-异丙基甲苯(天然生物衍生溶剂为萃取剂),混匀,然后迅速注入含有5 mL水和200 mg氯化钠的10 mL离心管中。离心8 min后,将离心管放入-18℃冷冻,取上层未被固化的萃取液进行分析。结果表明:3种甲氧基丙烯酸酯类杀菌剂的质量分数在0.5~100 mg·kg^(-1)内与其对应的峰面积呈线性关系,检出限为0.17 mg·kg^(-1);对燕麦、大麦、黑麦、高粱、小米等阴性样品进行加标回收试验,3种甲氧基丙烯酸酯类杀菌剂的回收率为90.5%~107%,测定值的相对标准偏差(n=5)均小于6.0%。

A method for the determination of residues of 3 methoxyacrylate fungicides,including azoxystrobin,pyraclostrobin and trifloxystrobin,in coarse grains by high performance liquid chromatography with dispersive liquid-liquid microextraction(DLLME) based on natural bioderived solvent was proposed.The sifted sample(1.0 g) was taken,and 800 μL of acetonitrile(as dispersant) was added for vortex.Then 500 μL of the supernatant was taken,and 200 μL of 4-isopropyl toluene(natural bioderived solvent as extractant) was added.After mixing well,the solution was quickly injected into a 10 mL-centrifuge tube containing 5 mL of water and 200 mg of sodium chloride.After centrifugation for 8 min,the centrifuge tube was frozen at-18 ℃,and the upper layer of unsolidified extract was taken for analysis.As shown by the results,linear relationships between values of mass fraction and peak area of 3 methoxyacrylate fungicides were kept in the range of 0.5-100 mg·kg^(-1),with detection limit of 0.17 mg·kg^(-1).Test for recovery was made on the negative samples of oat,barley,rye,sorghum and millet,giving results in the range of 90.5%-107%,and RSDs(n=5) of the determined values were less than 6.0%.